The invention relates to a method as recited in the preamble of Claim 1. For designing a digital circuitry concept, such method has been disclosed in U.S. Pat. No. 5,005,136. Broadly similar procedures may be followed for designs that have a substantial amount of analog circuit items or parameters, such as relating to oscillators, filters, amplifiers, and other items. The present inventors have recognized that most present-day design approaches for analog circuitry will start from a rigid circuit specification as provided by an IC-manufacturer. The latter will generally optimize the design with respect to attaining a small chip area and an optimized packing density. Such approach will result however in a highly inflexible solution, that may need much additional time and effort for generating redesigns and amendments in functionality or spec. Moreover, the design will in general feature only little or no possibility for the reuse of building blocks, due to the above focusing on area minimization. The above problem is especially relevant in the initial phases of designing a mass-product, where time-to-market is extremely critical, and where frequent redesign cycles are commonplace.
Now generally, the overall functional design will comprise a multiplicity of building blocks that are often arranged in a sequential type of organization for processing the signal or signals. Furthermore, the use of retrocoupling loops is a well-known feature. The various building blocks of such design may differ in layout view size among each other by several orders of magnitude.
The problem so sketched is further aggravated in that the designing environment, especially in the initial phases thereof, often has at least three players, to wit, the IC manufacturer, the set maker and the end user, who in principle should all benefit from an optimum design process. The present invention addresses in particular the designing for mass markets. This should lead to a product that will be accepted immediately as regards its features, operativity, and price. Time-to-market should generally be minimum.
The above problem is extremely relevant for analog-oriented circuit designs, inasmuch as for various parameters, such as voltage, frequency, etcetera, it is difficult to specify an exact optimum value in advance, but only a more or less broad range of values may be indicated. This uncertainty would often apply to various different parameters simultaneously, which renders the problem still more complex, and often quite unstable as regarding policy decisions. Furthermore, the design will often be bondpad-limited, in the sense that overall circuit size is strongly dependent on the number and configuration of the bondpads, so that the merits of area minimization are limited only.